A dispersion spectrum photosensitive component, a receiving end, and a lidar system

Abstract

The present invention discloses a dispersive spectral photosensitive component, comprising: a diaphragm, a collimating device, a filter, a dispersive device and an array detector sequentially arranged along the incident optical path; wherein, the diaphragm receives the signal light beam and the ambient light beam from the outside and collimates them into parallel beams by the collimating device, the filter filters the parallel beams and only allows the narrowband wavelength beam centered on the central wavelength of the signal light to pass through, and the dispersive device disperses the incident narrowband wavelength beam in one direction according to the wavelength, so that light of different wavelengths is incident on different positions on the surface of the array detector. By means of dispersion, the screening of the signal light wavelength is realized, thereby improving the signal-to-noise ratio and the measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical fields of optical sensors and lidar technology, and in particular, to a dispersion spectrum photosensitive component, a receiving end, and a lidar system. Background Art

[0002] Lidar is an active three-dimensional measurement technology. It emits laser beams into space through a laser transmitter, and then receives the laser beams reflected by objects through a receiving end. After processing the received optical signals, the flight time of the laser beams in space can be obtained. According to the relationship between distance, photon flight time, and the speed of light, the distance and azimuth information of the target can be calculated. Ambient light interference is a common problem faced by current lidar systems. That is, when a lidar works under strong outdoor light, it is often interfered by solar ambient light, resulting in a certain degree of decline in measurement distance and measurement accuracy.

[0003] To solve the problem of ambient light interference, in existing solutions, a near-infrared laser transmitter with relatively low solar spectral irradiance is often selected, and further ambient light filtering is performed by cooperating with a narrowband filter near this wavelength band at the receiving end. However, considering practical problems in engineering, such as the manufacturing tolerance of the center wavelength of the laser transmitter, the manufacturing tolerance of the center transmission wavelength of the filter, the drift of the center wavelength of the laser transmitter with temperature, etc., the full width at half maximum of the spectral transmittance of the actually used filter is much larger than the full width at half maximum of the laser wavelength. Therefore, the effect of ambient light filtering is very limited, resulting in low signal-to-noise ratio and measurement accuracy.

[0004] The disclosure of the above background art content is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. Without clear evidence indicating that the above content was publicly available on the filing date of this patent application, the above background art should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0005] The purpose of the present invention is to provide a dispersion spectrum photosensitive component, a receiving end, and a lidar system to solve at least one of the above background art problems.

[0006] To achieve the above object, the technical solution of the embodiment of the present invention is realized as follows:

[0007] A dispersive spectral photosensitive component, comprising: a diaphragm, a collimating device, a filter, a dispersive device, and an array detector arranged in sequence along the incident optical path; wherein, the diaphragm receives the signal light beam and the ambient light beam from the outside and is collimated into a parallel beam by the collimating device; the filter filters the parallel beam and only allows a narrow-band wavelength beam centered on the central wavelength of the signal light to pass through; the dispersive device disperses the incident narrow-band wavelength beam in one direction according to the wavelength, so that light of different wavelengths is incident on different positions on the surface of the array detector.

[0008] In some embodiments, the diaphragm includes at least one hole or a slit.

[0009] In some embodiments, the dispersive device includes at least one dispersive element, and the dispersive element includes a combination of one or more of a prism, a grating, a dispersive hologram, and a waveguide dispersive element.

[0010] In some embodiments, the dispersive device further includes a combination of one or more of a lens, a lens group, a microlens array, and a mirror.

[0011] In some embodiments, the waveguide dispersive element includes an incident coupler, a beam splitter, a combiner, an output coupler, and a waveguide.

[0012] In some embodiments, the array detector includes a plurality of pixels, and the pixels are SPADs.

[0013] In some embodiments, the collimating device includes a waveguide transmission element, and the waveguide transmission element includes an incident coupler, a waveguide, and an output coupler.

[0014] In some embodiments, the filter can also be placed outside the diaphragm, or between the diaphragm and the collimating device, or between the collimating device and the dispersive device, or between the dispersive device and the array detector in the optical path.

[0015] Another technical solution of the embodiment of the present invention is:

[0016] A receiving end of a dispersive spectral lidar, comprising: a receiving optical component for receiving at least a part of the signal light beam reflected back by the target and a part of the ambient light beam and incident into the dispersive spectral photosensitive component described in any one of the above embodiment technical solutions, and the dispersive spectral photosensitive component disperses the incident beam to distinguish different wavelengths in space.

[0017] Another technical solution of the embodiment of the present invention is:

[0018] A dispersion spectroscopic lidar system, comprising: a transmitting end configured to transmit a signal light beam; a dispersion spectroscopic lidar receiving end as described in the technical solution of the foregoing embodiment; a control and processor for controlling a dispersion spectroscopic photosensitive component in the dispersion spectroscopic lidar receiving end to filter out an incident beam signal having the same wavelength as the signal light beam, and calculating the flight time of photons based on the incident beam signal.

[0019] The beneficial effects of the technical solution of the present invention are:

[0020] In view of the problem of ambient light interference in lidar, the present invention proposes a dispersion-based spectroscopic lidar system, which can more effectively reduce the influence of ambient light and improve the detection range and accuracy of the lidar. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0022] Figure 1 It is a schematic diagram of the composition of a dispersion spectroscopic lidar according to an embodiment of the present invention;

[0023] Figure 2 It is a schematic diagram of a mechanically scanned dispersion spectroscopic lidar system according to an embodiment of the present invention;

[0024] Figure 3 It is a schematic diagram of a non-mechanically scanned dispersion spectroscopic lidar system according to an embodiment of the present invention;

[0025] Figure 4 It is a schematic diagram of the composition of a dispersion spectroscopic lidar receiving end according to an embodiment of the present invention;

[0026] Figure 5a It is a schematic diagram of a waveguide transmission element according to an embodiment of the present invention;

[0027] Figure 5b It is a schematic diagram of a waveguide dispersion element according to an embodiment of the present invention;

[0028] Figure 6 It is a schematic diagram of a lidar system receiving end containing a planar array dispersion spectroscopic photosensitive component according to an embodiment of the present invention;

[0029] Figure 7 It is a schematic diagram of a planar array dispersion spectroscopic lidar receiving end according to an embodiment of the present invention;

[0030] Figure 8 It is a schematic diagram of the receiving end of a planar array dispersion spectroscopic lidar according to another embodiment of the present invention;

[0031] Figure 9 It is a schematic diagram of the receiving end of a planar array dispersion spectroscopic lidar according to yet another embodiment of the present invention;

[0032] Figure 10 It is a schematic diagram of the receiving end of a planar array dispersion spectroscopic lidar according to yet another embodiment of the present invention;

[0033] Figure 11 It is a schematic diagram of the receiving end of a planar array dispersion spectroscopic lidar according to yet another embodiment of the present invention. Detailed implementation manners

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the embodiments of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, the connection can be for a fixing function or for a circuit connection function.

[0036] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0037] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0038] Figure 1The figure shows a schematic diagram of a dispersion spectral lidar system according to an embodiment of the present invention. The system 10 includes a transmitting end 12, a receiving end 15, and a control and processor 11. Among them, the transmitting end 12 includes a light source 13 and a transmitting optical component 14. The receiving end 15 includes a dispersion spectral photosensitive component 16 and a receiving optical component 17. The transmitting end 12 emits a laser beam within a specific wavelength range (also known as: signal light beam) through the light source 13, such as a laser beam with a wavelength near 960nm or 1550nm. This laser beam group is modulated by the transmitting optical component 14 and then emitted towards the target space. The receiving optical component 17 in the receiving end 15 is used to collect at least part of the laser beam reflected by an object in the target space and other beams from ambient light, and incident them into the dispersion spectral photosensitive component 16. The dispersion spectral photosensitive component 16 disperses the received beams to spatially distinguish the incident beams according to different wavelengths. The spatial positions where the beams of different wavelengths fall are different. The control and processor 11 controls the dispersion spectral photosensitive component 16 and filters out only the incident beam signal that is consistent with the central wavelength of the signal beam emitted by the transmitting end 12 (specifically, a narrowband wavelength beam signal within a very small interval centered on the central wavelength of the transmitted signal beam. In theory, this interval range should include most of the signal light beams and a very small number of ambient light beams), and calculates the flight time of photons based on this incident beam signal. Further, the distance D of the target is calculated based on this flight time, that is:

[0039] D = c·t / 2 (1)

[0040] Where c is the speed of light and t is the flight time.

[0041] Preferably, the dispersion spectral photosensitive component 16 includes a dispersion device and a photosensitive detector. The dispersion device disperses the incident beam and emits it at different angles according to the wavelength, so that the beams of different wavelengths are incident on different spatial positions of the photosensitive detector, which is convenient for subsequent screening. Specific embodiments of the dispersion spectral photosensitive component 16 will be introduced in detail later.

[0042] The dispersion function of the dispersion spectral photosensitive component enables the incident beam to be spatially distinguished according to the wavelength, thereby screening out the signal light. Compared with filtering only through a filter, the dispersion can very accurately locate the signal light. The bandwidth of the screened narrowband beam is smaller than that of the filter, and at the same time, most of the ambient light noise can be filtered out, thus greatly improving the accuracy and signal-to-noise ratio of the lidar system.

[0043] According to the functional and performance requirements of different lidars, the system can be designed in different styles. For example, for a long-range lidar, the transmitting end 12 will emit a high-power laser beam, which is pre-modulated into shapes such as spots and lines, and the field of view covered by the entire laser beam is relatively small; while for a short-range lidar, the transmitting end 12 can be configured to emit a low-power laser beam with a certain field of view, and the laser beam can be in the shape of floodlight, spot, line, etc. Similarly, the receiving end 15 is also specially designed to correspond to the transmitting end. Several specific embodiments will be introduced in detail later.

[0044] In one embodiment, the transmitting end 12 is used to emit a single laser beam 18 into space, and the laser beam 18 has a certain cross-sectional shape 20, such as circular spot shape, elliptical shape, linear shape, etc. Correspondingly, the receiving beam assembly 17 in the receiving end 15 is used to collect the light beams within a certain field of view 19, and the field of view 19 of the receiving end 15 is designed to exactly correspond to the laser beam 18 through certain design, so that the receiving end can collect the laser beams reflected by the objects in the target space, and then further calculate the flight time. Generally, the field of view 19 is larger than the divergence angle of the laser beam 18. For the convenience of description, in the embodiments of the present invention, a laser beam and the field of view of the receiving end corresponding to the laser beam are called a channel, and the transmitting channels of the transmitting end and the receiving channels of the receiving end correspond one by one, so as to realize the distance measurement of the target object. The channel can be any form of channel such as a point channel, a line channel, a coded channel, etc.

[0045] Figure 1 Only a single channel is schematically drawn in the figure. In other embodiments, the system 10 can achieve distance measurement with a larger field of view by scanning a single channel or multiple channels. For example, in one embodiment, beam scanning devices such as MEMS mirrors and mechanical rotating mirrors are arranged in the transmitting optical assembly 14 and / or the receiving optical assembly 17 to achieve beam scanning, so as to achieve multi-channel measurement. Of course, an additional beam scanning assembly can also be added to achieve this. In one embodiment, the transmitting end 12 can simultaneously emit multi-channel laser beams. Correspondingly, the receiving end 15 also has a plurality of receiving channels corresponding one by one to the transmitting channels of the transmitting end 12, so that multi-channel (such as dot matrix, line matrix, etc.) scanning of the target can be realized simultaneously.

[0046] In some embodiments, the transmitting end 12 and the receiving end 15 are arranged in a coaxial form. For example, it can be achieved by adding optical elements such as a semi-transmissive and semi-reflective mirror with reflection and transmission functions, and a transmissive and reflective mirror with a hole in the middle of the mirror. The coaxial form can ensure the one-to-one correspondence between the transmitting channel and the receiving channel. In some embodiments, the transmitting end 12 and the receiving end 15 are arranged in an off-axis form. Compared with the coaxial form, the off-axis form has lower requirements for hardware and is convenient for assembly. The disadvantage is that the problem of parallax needs to be considered. When the target is at different distances, there will be a deviation between the transmitting channel and the receiving channel due to parallax. It can be understood that when the measured distance is much larger than the baseline distance between the transmitting end and the receiving end, the problem of parallax can also be ignored. When the measured distance is relatively close, the parallax problem can be solved by calibration, spot positioning and other methods.

[0047] In some embodiments, the transmitting end and the receiving end are installed on the same substrate to facilitate the miniaturization and integration of the system. For example, a laser light source and a photosensitive chip can be simultaneously fabricated on the same semiconductor substrate through semiconductor processes, and then optical devices, electronic components, etc. are further installed on the semiconductor substrate to form the transmitting end and the receiving end.

[0048] In some embodiments, the dispersive spectral lidar is configured as a lidar system in a mechanical scanning form, such as Figure 2 shown, the lidar system in the mechanical scanning form includes a transmitting end 201, a receiving end 202, and a rotating platform 203 for placing the transmitting end and the receiving end. The rotating platform 203 can be rotated along a certain direction 204 through a rotating component under the control of the control and processor 11, so as to achieve scanning of a large field of view angle (such as 360 degrees).

[0049] In some embodiments, the dispersive spectral lidar is configured as a lidar system in a non-mechanical scanning form, such as Figure 3 shown, the transmitting end 12 and the receiving end 15 of the lidar system in the non-mechanical scanning form are configured to have a common field of view 31. Generally, the transmitting end 12 is used to emit laser beams of multiple channels to illuminate the target within the common field of view angle, and the receiving end 15 is used to collect the laser beams reflected back from within the common field of view angle.

[0050] Based on the dispersive spectral lidar systems described in the above embodiments, the embodiments of the present invention further provide a method for measurement based on the above dispersive spectral lidars, and the method includes the following steps:

[0051] First, emit a signal light beam;

[0052] Second, receive at least part of the signal light beam reflected back by the target and part of the ambient light beam;

[0053] Next, the received incident light beam is dispersed to spatially distinguish light beams of different wavelengths;

[0054] Finally, the incident light beam signal with the same wavelength as the signal light beam is screened out, and the flight time of photons is calculated based on the incident light beam signal.

[0055] The above steps are specifically implemented by Figures 1-3 the dispersion spectral lidar system in the illustrated embodiment. For the detailed method steps, reference can be made to Figures 1-3 the description in the illustrated embodiment, which will not be elaborated here.

[0056] Figure 4 FIG. 15 is a schematic diagram of the composition of the receiving end of a dispersion spectral lidar according to an embodiment of the present invention. The receiving end includes a dispersion spectral photosensitive component 41 and a receiving optical component 42; among them, the receiving optical component 42 is composed of at least one lens or lens array, and is used to receive a part of the laser beam (signal light) reflected back by an object 46 in the target space and other ambient light beams from the environment. In this embodiment, a bar-shaped laser beam emitted by the transmitting end will be used as an example for illustration. It can be understood that the present invention is not limited to bar-shaped beams. The object 46 will reflect a bar-shaped beam 47 (including signal light and ambient light), which is collected by the receiving optical group 42 and incident on the dispersion spectral photosensitive component 41.

[0057] The dispersion spectral photosensitive component 41 includes a diaphragm 415, a collimating device 414, a filter 413, a dispersion device 412, and an array detector 411 arranged in sequence along the incident optical path; the beam 47 reflected back by the object 46 converges to the plane of the diaphragm 415 after passing through the receiving optical component 42; the diaphragm limits the field of view angle of the receiving optical component 42, and only the reflected beam received within this field of view angle can pass through the diaphragm and further be incident on the collimating device 414; the collimating device 414 collimates the reflected beam passing through the diaphragm into a parallel beam, and this parallel beam is then incident on the filter 413; the filter 413 is a band-pass filter, which is used to filter the incident light beam and only allows narrow-band wavelength light beams within a certain bandwidth range centered on the central wavelength of the signal light to pass through; generally, the passband wavelength of the filter 413 is set to be centered on the central wavelength of the signal light, and the full width at half maximum of the transmittance is usually dozens of nanometers (only as an example). However, since the full width at half maximum of the signal light is much narrower than the bandwidth of the filter, most of the signal light and the ambient light near the central wavelength of the signal light in the ambient light will pass through the filter.

[0058] The narrowband wavelength light beam emitted by the filter 413 is incident on the dispersion device 412. The dispersion device 412 disperses the incident narrowband wavelength light beam in one direction according to the wavelength, so that light of different wavelengths irradiates different positions on the surface of the array detector 411. For example, a plurality of light beams 43, 44, 45 arranged along the wavelength are formed on the surface of the array detector 411. Thus, some pixels of the array detector 411 (such as 44) are only irradiated by the signal light and the ambient light having the same wavelength as the signal light, and the ambient light having a wavelength different from the signal light will no longer overlap with the signal light in space, such as 43, 45. Subsequently, the control and processor can only read out the signals in the corresponding pixels on the array detector 411 in the signal light band, and calculate the flight time of the photons based on the read optical signal. Further, the distance to the target can be calculated according to the flight time. By dispersing and differentiating in space, the ambient light in the narrowband wavelength light beam from the filter can be further filtered out. Through the reasonable design of the dispersion device and the design of the array detector, in theory, only the light beams within the signal light bandwidth can be screened out. Therefore, compared with the filtering effect of only the filter, the noise from the ambient light can be further significantly reduced, and finally the suppression effect on the ambient light is achieved, improving the measurement accuracy and signal-to-noise ratio.

[0059] The aperture 415 is generally arranged on the focal plane of the receiving optical component 42, and at least one hole or one slit is included on the aperture 415. The arrangement form and quantity of the set holes or slits determine the optical properties such as the field of view angle and resolution of the dispersion spectrum photosensitive component 41; generally, the aperture is set in a reasonable form according to the overall performance requirements of the lidar system. For example, for a single-channel lidar, if the emitting end emits a line light beam, the aperture can only include a single linear hole, that is, a single-slit aperture; if the emitting end emits a dot light beam, the aperture can only include a single round hole, that is, a single-hole aperture. When the emitting end emits a planar light beam, the aperture can include a plurality of slits or a plurality of holes arranged in an array, that is, a multi-slit aperture or a multi-hole aperture. Thus, array optical signals can be synchronously received to obtain depth measurement information of the array, which will be described in detail later.

[0060] The position of the aperture through-hole or slit in the plane of the aperture can be fixed or movable. When the position of the aperture through-hole or slit is movable, the movement amount of the through-hole or slit position is controlled by the control and processor. The movable aperture includes but is not limited to being realized by a MEMS mechanism, a liquid crystal device, etc. In one embodiment, the opening and closing of the aperture through-hole or slit can also be controlled by the control and processor. For a multi-hole or multi-slit aperture, the holes or slits on the aperture can be arranged in a one-dimensional or two-dimensional arrangement form as needed, such as a regular two-dimensional array, an irregular two-dimensional array, etc.

[0061] In some embodiments, the array detector 411 is an array-type optical receiving device composed of multiple pixels. Typically, there are APD (avalanche photodiode) arrays and SPAD (single-photon avalanche diode) arrays. The array detector can measure the flight time of the signal light reflected from the target back to the array detector. The pixels on the array detector include at least one column of pixels in the direction consistent with the dispersion direction.

[0062] In some embodiments, the collimating device can be composed of one or a combination of at least one lens, microlens array, mirror (including various types of mirrors such as plane mirrors, curved mirrors, and reflecting prisms), and waveguide transmission elements.

[0063] Regarding the waveguide transmission element, reference can be made to Figure 5a as shown Figure 5a is a schematic diagram of a waveguide transmission element according to an embodiment of the present invention. The waveguide transmission element is composed of an input coupler 51, a waveguide 52, and an output coupler 53, and is used to transmit the incident light beam in three-dimensional space and emit it outward in a certain direction at a suitable position. The waveguide transmission element can make the function of the collimating device more extensive. For example, it can control the spatial position and emission direction of the output collimated light beam according to needs, which will be described later. The waveguide 52 in the waveguide transmission element can be an optical fiber. The waveguide can transmit the light beam along a curved path in three-dimensional space. The input coupler 51, the output coupler 53, and the waveguide 52 can be independent off-chip devices, or can be realized by on-chip optical paths, or can be a combination of on-chip devices and discrete off-chip devices.

[0064] In some embodiments, the filter 413 can be placed at other positions in the optical path. For example, it can be placed outside the diaphragm 415 (including between the receiving optical component 42 and the target object 46, or between the diaphragm 415 and the receiving optical component 42), or between the diaphragm 415 and the collimating device 414, or between the collimating device 414 and the dispersion device 412, or between the dispersion device 412 and the array detector 411; preferably, the filter 413 is placed between the collimating device 414 and the dispersion device 412.

[0065] The dispersion device 412 includes at least one dispersion element, such as a combination of one or more of a prism, a grating, and a dispersion hologram. It can form output light beams with different emission angles for the incident light beam according to different wavelengths, thereby achieving the dispersion effect of the light beam. Among them, the dispersion hologram is a holographic device that simultaneously has a dispersion function and a focusing function (or a diverging function). In some embodiments, in addition to the dispersion element, the dispersion device 412 also includes a combination of one or more of a lens, a lens group, a microlens array, and a mirror.

[0066] In some embodiments, the dispersion element can also be a waveguide dispersion element, such asFigure 5b As shown. The waveguide dispersion element includes an input coupler 54, a beam splitter 56, a combiner 57, an output coupler 58, and a waveguide 55. The incident light of the waveguide dispersion element is coupled into a single waveguide 55 through the input coupler 54, and the other end of the waveguide is connected to the beam splitter 56. The beam splitter 56 distributes its incident light into multiple waveguides connected between the beam splitter 56 and the combiner 57 with equal intensity or unequal intensity and equal phase. For convenience of description, it is described with N waveguides. The lengths of these N waveguides increase in a fixed increment. The number of N needs to be designed according to the dispersion resolution of the waveguide dispersion element. Generally, the larger the value of N, the higher the dispersion resolution of the waveguide dispersion element. Since the lengths of these N waveguides increase, there is a constant phase difference between the output lights of these N waveguides; however, due to the different effective refractive indices of the waveguide for light waves of different wavelengths, the phase differences formed by light waves of different wavelengths after passing through these N waveguides are different. Therefore, the positions of constructive interference of light waves of different wavelengths in the combiner 57 are different. At the position of constructive interference of the light wave with the central wavelength of the signal light in the combiner, a waveguide is used to connect this position to the output coupler 58, and the signal light and the ambient light with a wavelength close to that of the signal light (i.e., the light beam with the same central wavelength as the signal light) can be led out from the combiner 57.

[0067] In some embodiments, the waveguide 55 in the waveguide dispersion element can be an optical fiber. The waveguide can transmit the light beam along a curved path in three-dimensional space. The beam splitter 56, the input coupler 54, the combiner 57, the output coupler 58, and the waveguide 55 can be independent off-chip devices, or can be implemented by an on-chip optical path, or can be a combination of on-chip devices and discrete off-chip devices.

[0068] In the above embodiments, the dispersive spectral photosensitive component capable of single-channel measurement is taken as an example for elaboration. However, in some other applications, it is often necessary for the lidar system to synchronously perform multi-channel measurement to obtain a large field of view / higher resolution measurement. In the following embodiments, a planar array dispersive spectral lidar containing a planar array dispersive spectral photosensitive component capable of multi-channel measurement will be provided. The content of the above dispersive spectral photosensitive component is equally applicable to the planar array dispersive spectral photosensitive component described in the following embodiments.

[0069] Figure 6Schematic diagram of the receiving end of a lidar system containing a planar array dispersive spectral photosensitive component according to an embodiment of the present invention. The receiving end includes a planar array dispersive spectral photosensitive component 61 and a receiving optical component 62. Among them, the receiving optical component 62 is composed of at least one lens or lens array, and is used to collect a part of the laser beam (signal light) reflected by an object in the target space and other ambient light beams from the environment, such as reflected beams 631, 632, and 633 from different field-of-view regions (different channels) in the field of view. The reflected beams are collected by the receiving optical component 62 and incident on the planar array dispersive spectral photosensitive component 61. The planar array dispersive spectral photosensitive component 61 includes a planar array diaphragm 615, a collimating device 614, a filter 613, a dispersive device 612, and a planar array detector 611 arranged in sequence along the incident optical path.

[0070] A plurality of holes or slits arranged in a planar array are provided on the planar array diaphragm 615, and each hole or slit is used to receive the light beam within the corresponding incident field-of-view angle of the corresponding receiving optical component 62, such as Figure 6Schematically shown are 3 holes or slits respectively for receiving incident light beams 631, 632 and 633 from three different directions. For the convenience of illustration, only three channels are taken as examples here, but it should not be understood as being limited to only three channels. The number and arrangement form of the holes or slits on the area array aperture 615 determine the field of view angle and imaging resolution of the entire photosensitive component 61. Each light beam passing through the area array aperture 615 further enters the collimating device 614; the collimating device 614 collimates the light beam passing through the aperture into a multi-channel parallel light beam, and this parallel light beam then enters the filter 613; the filter 613 is a band-pass filter for filtering the incident light beam, and only allows narrow-band wavelength light beams within a certain bandwidth range centered on the central wavelength of the signal light to pass through. The narrow-band wavelength light beam emitted from the filter 613 enters the dispersion device 612, and the dispersion device 612 disperses the incident narrow-band wavelength light beam along at least one direction according to the wavelength, so that light of different wavelengths irradiates different positions on the surface of the area array detector 611. For example, a plurality of light beams a, b, c arranged along the wavelength are formed on the surface of the area array detector 611 (only three light beams are taken as examples for illustration, and actually there can be more light beams). The area array detector 611 includes a plurality of pixels 616 arranged in a two-dimensional area array (such as pixels such as APD, SPAD, etc.). Generally, the total number of pixels is greater than the total number of holes or slits on the area array aperture. Preferably, corresponding pixel groups are respectively set on the area array detector 611 for each hole or slit, and each pixel group is spatially independent and is used to respectively receive the light beam transmitted from its corresponding aperture hole or slit. Due to the effect of dispersion, light beams a, b, c of different wavelengths will enter different positions in the pixel group. If the wavelength of the b light beam is the same as the wavelength of the signal light, the signal generated by the pixel for receiving the b light beam will be read out by the subsequent control and processor, and the flight time of the photon can be calculated based on the read optical signal. Further, the distance to the target can be calculated according to the flight time. Since environmental light of other bands is filtered out, the noise from environmental light is greatly reduced, and finally the suppression effect on environmental light is achieved, and the measurement accuracy is improved.

[0071] In some embodiments, the collimating device 614 may be composed of one or a combination of at least one lens, a microlens array, a mirror (including various types of mirrors such as a plane mirror, a curved mirror, a reflecting prism, etc.), and an area array waveguide transmission element.

[0072] In some embodiments, the dispersion device 612 includes a dispersion element, and the dispersion element may be a combination of one or more of a prism, a grating, and a dispersion hologram. The dispersion device 612 may further include a converging lens, which may be composed of one or a combination of at least one lens, a microlens array, and a mirror.

[0073] In some embodiments, the dispersion device 612 may also be an area array waveguide dispersion element, which is composed of a plurality of such asFigure 5a , Figure 5b It is composed of the waveguide dispersion element arrangement shown. Each waveguide dispersion element in the area array waveguide dispersion element corresponds one-to-one with the holes or slits on the diaphragm, and is respectively used to receive the light beams transmitted from the corresponding holes or slits.

[0074] For the area array dispersion spectral lidar, in order to enable the lidar system to achieve better performance, it is necessary to consider the collimation device and the dispersion device as a whole to design the corresponding receiving end of the area array dispersion spectral lidar. Several receiving end embodiments will be proposed below according to the main idea of the present invention.

[0075] Figure 7 It is a schematic diagram of the receiving end of the area array dispersion spectral lidar according to an embodiment of the present invention. The receiving end includes an area array dispersion spectral photosensitive component 71 and a receiving optical component 72; wherein, the receiving optical component 72 is composed of at least one lens or a lens array, and is used to collect part of the laser beam (signal light) reflected back by the object in the target space and other ambient light beams from the environment, such as the reflected beams 731, 732, and 733 from different field-of-view regions (different channels) in the field of view. The reflected beams are collected by the receiving optical component 72 and incident on the area array dispersion spectral photosensitive component 71. The dispersion spectral photosensitive component 71 includes an area array diaphragm 715, a first microlens array 714, a filter 713, a dispersion device 712, and an area array detector 711.

[0076] The area array diaphragm 715 is provided with a plurality of holes or slits arranged in an area array, and each hole or slit is used to receive the light beam within the corresponding incident field of view (channel) of the corresponding receiving optical component 72. Each light beam passing through the area array diaphragm 715 further enters the first microlens array 714; each microlens in the first microlens array 714 corresponds one-to-one with the hole or slit in the area array diaphragm 715, and respectively collimates the light beam passing through the diaphragm into a parallel light beam, and the parallel light beam then enters the filter 713; the filter 713 allows the narrow-band wavelength light beam within a certain bandwidth range centered on the central wavelength of the signal light to pass through, and the passed narrow-band wavelength light beam then enters the dispersion device 712. The dispersion device 712 includes a dispersion element 717 and a second microlens array 716. The dispersion element 717 can be one or a combination of a prism, a grating, and a dispersion hologram, and is used to disperse the incident narrow-band wavelength light beam along at least one direction according to the wavelength; each microlens in the second microlens array 716 corresponds one-to-one with each microlens in the first microlens array 714 or the hole or slit in the area array diaphragm 715, and is used to converge / focus the light beam from the dispersion element 717 to be incident on the corresponding pixel on the area array detector 711. Due to the dispersion effect of the dispersion element 717, the light beams from the same diaphragm will be incident on different pixels according to different wavelengths, so that their spatial separation is achieved, and finally the pixel signals of the pixels receiving the light beam consistent with the signal light wavelength are subsequently read out by the control and processor.

[0077] Figure 8 It is a schematic diagram of the receiving end of an area array dispersion spectrum lidar according to another embodiment of the present invention. The receiving end includes an area array dispersion spectrum photosensitive component 81 and a receiving optical component 82; wherein, the receiving optical component 82 is composed of at least one lens or a lens array, and is used to collect a part of the laser light beam (signal light) reflected back by an object in the target space and other ambient light beams from the environment, such as the reflected light beams from different field of view regions (different channels) in the field of view. For the convenience of illustration, only the channel 831 is taken as an example in this embodiment, and the reflected light beam is collected by the receiving optical component 82 and enters the area array dispersion spectrum photosensitive component 81. The dispersion spectrum photosensitive component 81 includes an area array diaphragm 815, a first microlens array 814, a filter 813, a dispersion device 812, and an area array detector 811.

[0078] Different from Figure 7 the embodiment shown, Figure 8The dispersion device 812 in the illustrated embodiment includes a second microlens array 819, a first lens 818, a dispersion element 817, and a second lens 816 arranged in sequence along the optical path. Among them, each microlens in the second microlens array 819 corresponds one-to-one with each microlens in the first microlens array 814 or the holes or slits in the area array aperture 815, and is used to receive and converge the collimated light beam collimated by the first microlens array 814; the first lens 818 receives the light beam converged by the second microlens array 819, collimates and expands it, and the expanded parallel light beam is then incident on the dispersion element 817. After dispersion, it is incident on the second lens 816. The second lens 816 is used to converge or focus the dispersed light beam to be incident on the corresponding pixels on the area array detector 811. Due to the dispersion effect of the dispersion element 817, light beams of different wavelengths are incident on the second lens 816 in different directions, so that the light beams from the same aperture are incident on different pixels according to different wavelengths, so that their separation in space is achieved. Finally, the pixel signals of the pixels that receive the light beam consistent with the signal light wavelength are subsequently read out by the control and processor. Among them, the first lens 818 and the second lens 816 can be a single-piece lens or a lens group composed of multiple lenses.

[0079] Figure 9 FIG. is a schematic diagram of the receiving end of an area array dispersion spectral lidar according to another embodiment of the present invention. The receiving end includes an area array dispersion spectral photosensitive component 91 and a receiving optical component 92. Among them, the receiving optical component 92 is composed of at least one lens or a lens array, and is used to collect a part of the laser beam (signal light) reflected back by an object in the target space and other ambient light beams from the environment, such as reflected light beams 931, 932, and 933 from different field-of-view regions (different channels) in the field of view. The reflected light beams are collected by the receiving optical group 92 and incident on the area array dispersion spectral photosensitive component 91.

[0080] different from Figure 7 and Figure 8 the illustrated embodiment is that Figure 9 the dispersion device 912 in the embodiment includes an area array waveguide dispersion element 912 composed of a plurality of waveguide dispersion elements 916. Each of the waveguide dispersion elements 916 is respectively used to receive the light beam from the corresponding aperture hole or slit, and selectively output the light beam consistent with the central wavelength of the signal light to be incident on the corresponding pixels of the area array detector 911. Generally, each of the waveguide dispersion elements 916 on the area array waveguide dispersion element 912 corresponds one-to-one with each of the microlenses on the first microlens array 914 or with each of the holes or slits on the aperture 915, including one-to-one correspondence in terms of quantity and / or arrangement.

[0081] InFigures 7-9 In the illustrated embodiments, the collimating device is a microlens array. In fact, other devices such as lenses (lens groups), waveguide transmission elements, etc. can also be used. Two specific embodiments will be exemplarily introduced below.

[0082] Referring to Figure 10 as shown, Figure 10 is a schematic diagram of the receiving end of a planar array dispersive spectral lidar according to another embodiment of the present invention. The receiving end includes a planar array dispersive spectral photosensitive component 101 and a receiving optical component 102. Among them, the dispersive spectral photosensitive component 101 includes a planar array diaphragm 1015, a first lens 1014, a filter 1013, a dispersive device 1012, and a planar array detector 1011.

[0083] A plurality of holes or slits arranged in a planar array are provided on the planar array diaphragm 1015, and each hole or slit is used to receive the light beam within the corresponding incident field of view angle of the corresponding receiving optical component 102. Each light beam passing through the planar array diaphragm 1015 further enters the first lens 1014, and the first lens 1014 collimates the light beam passing through the diaphragm into a parallel light beam, and the parallel light beam then enters the filter 1013; the filter 1013 allows the narrowband wavelength light beam within a certain bandwidth range centered on the central wavelength of the signal light to pass through, and the passed narrowband wavelength light beam then enters the dispersive device 1012. The dispersive device 1012 includes a dispersive element 1017 and a second lens 1016. The dispersive element 1017 is used to disperse the incident narrowband wavelength light beam along at least one direction according to the wavelength; the second lens 1016 cooperates with the first lens 1014 to converge / focus the incident parallel light beam to the corresponding pixel on the planar array detector 1011. Due to the dispersion effect of the dispersive element 1017, the light beams from the same diaphragm will be incident on different pixels according to different wavelengths, so that their spatial separation is achieved, and finally the pixel signals of the light beams consistent with the signal light wavelength are read out by the subsequent control and processor. Among them, the first lens 1014 and the second lens 1016 can be a single-piece lens or a lens group composed of multiple lenses.

[0084] Referring to Figure 11 as shown, Figure 11 is a schematic diagram of the receiving end of a planar array dispersive spectral lidar according to another embodiment of the present invention. The receiving end includes a planar array dispersive spectral photosensitive component 111 and a receiving optical component 112; among them, the dispersive spectral photosensitive component 111 includes a planar array diaphragm 1115, a collimating device 1114, a filter 1113, a dispersive device 1112, and a planar array detector 1111.

[0085] The area array diaphragm 1115 is provided with a plurality of holes or slits arranged in an area array, and each hole or slit is used to receive the light beam within the corresponding incident field angle of the corresponding receiving optical component 112. Each light beam passing through the area array diaphragm 1115 further enters the collimating device 1114. The collimating device 1114 includes an area array waveguide transmission element composed of a plurality of waveguide transmission elements 117. Each of the waveguide transmission elements 117 is respectively used to receive the light beam from the corresponding diaphragm hole or slit, and transmit and collimate the light beam and then emit it. Generally, each of the waveguide transmission elements 117 on the area array waveguide transmission element corresponds one-to-one with each of the holes or slits on the diaphragm 1115, and the one-to-one correspondence includes the one-to-one correspondence in terms of quantity and / or arrangement. In one embodiment, the collimating device 1114 further includes lenses arranged at the incident coupler and / or the output coupler ends of each waveguide transmission element, such as the first microlens array 116 and / or the second microlens array 118. Each microlens in the microlens array corresponds one-to-one with each of the waveguide transmission elements.

[0086] The parallel light beam collimated by the collimating device 1114 then enters the filter 1113; the filter 1113 allows the narrowband wavelength light beam within a certain bandwidth range centered on the central wavelength of the signal light to pass through, and the passed narrowband wavelength light beam then enters the dispersive device 1112. The dispersive device 1112 includes a dispersive element 115 and a third microlens array 114. The dispersive element 115 is used to disperse the incident narrowband wavelength light beam along at least one direction according to the wavelength; each microlens in the third microlens array 114 corresponds one-to-one with each of the waveguide transmission elements 117 in the area array waveguide transmission element and / or each of the holes or slits on the diaphragm 1115, and is used to converge / focus the light beam from the dispersive element 115 to enter the corresponding pixel on the area array detector 1111.

[0087] In Figure 9 the embodiment, a planar array waveguide dispersive element is adopted in the dispersive element of the dispersive spectral photosensitive component. In Figure 11 the embodiment described above, the collimating device adopts an area array waveguide transmission element. Since the waveguide can transmit the light beam along a curved path in three-dimensional space, the multiple output couplers in the area array waveguide dispersive (transmission) element can be rearranged or the direction can be adjusted in space, and can be rearranged relative to the spatial arrangement of the multiple input couplers to achieve the arrangement and / or direction of the output light beam required by the system. For example, due to the arrangement requirement of the pixels on the area array detector, in order to more evenly introduce the light beam in each diaphragm aperture into the corresponding pixel, the arrangement and / or direction of the output couplers can be readjusted to achieve a flexible configuration of the mapping relationship between the diaphragm aperture and the detector pixel.

[0088] It is understandable that any device with the same function as the collimating device can be used to replace the collimating device in the dispersion spectrum photosensitive component. Similarly, any device with the same function as the dispersion element can be used to replace the dispersion element. Moreover, the combination method of the collimating device and the dispersion element is not limited to the several types in the above embodiments. Any combination based on the idea of the present invention and capable of realizing similar functions belongs to the protection scope of the present invention.

[0089] The transmitting end of the dispersion spectrum lidar will be described later. Referring to Figure 1 , the transmitting end 12 includes a light source 13 and a transmitting optical component 14, and is used to emit at least one channel of laser beam (signal light beam) into space. For different application requirements, the transmitting end can be configured in different forms.

[0090] In some embodiments, the transmitting end is used to emit a speckle beam, and the emitted speckle beam can be a single-point light spot or a multi-point light spot. In order to obtain high-spatial-resolution point cloud data within the measurement field of view, a scanning element can also be added to the transmitting optical component 14 in one embodiment. In addition, the transmitting optical component 14 also includes beam shaping elements, such as lenses, mirrors, etc., which are used to shape the divergent beam emitted by the light source into a single-point or multi-point light spot and irradiate it onto the target. It is understandable that when the transmitting end only emits a single-point light spot, only one light-passing hole is required for the diaphragm in the corresponding receiving end, and this light-passing hole is located on the optical axis of the receiving system; when the reflecting end emits multiple point light spots, the diaphragm has multiple light-passing holes, and each light-passing hole corresponds one-to-one to each point light spot emitted. For multi-point light spots, they can be arranged in a line or two-dimensionally in the x direction and the y direction.

[0091] In some embodiments, the transmitting end is used to emit a single-line light spot or a multi-line light spot. Similarly, in order to obtain high-spatial-resolution point cloud data within the measurement field of view, a scanning element can also be added to the transmitting optical component 14 in one embodiment. In addition, the transmitting optical component 14 also includes beam shaping elements, such as lenses, mirrors, etc., which are used to shape the divergent beam emitted by the light source into a single-line or multi-line light spot and irradiate it onto the target. Generally, the line light spot has a smaller beam divergence angle in one direction, such as 0.05° - 0.15°, while the divergence angle in the other direction reaches several tens of degrees. When the emitted light spot is a multi-line light spot, each line is parallel to each other.

[0092] In the point light spot and line light spot embodiments, the light source at the emitting end can be a single-point edge-emitting laser, a single-point vertical-cavity surface-emitting laser (VCSEL), an emitting laser array composed of multiple edge-emitting lasers, a VCSEL array, and a VCSEL with controllable zones, etc. The beam shaping device is composed of a combination of one or more of a lens, a microlens array, a Metasurface device, a beam splitting prism, and a mirror. The scanning element can be composed of an MEMS mirror, a rotating prism, a pair of rotating prisms, a mechanical galvanometer, an OPA scanning device, etc.

[0093] In some embodiments, the emitting end can directly emit multiple point light spots without passing through a scanning element. The emitting end includes a planar array light source composed of multiple sub-light sources and an emitting optical component. The divergent light beams emitted by the sub-light sources are shaped into point light spots or line light spots by the beam shaping element in the emitting optical component and then emitted into space. The processing and controller can perform zonal lighting on the multiple sub-sources in the planar array light source, and only select the corresponding pixels on the detector at the receiving end when the sub-light sources in the corresponding area are lit, so as to achieve scanning measurement in at least one direction. The light source can be multiple edge-emitting lasers that can be sequentially lit, multiple VCSEL lasers that can be sequentially lit, a VCSEL planar array laser that can be zoned and lit, etc.

[0094] It can be understood that when corresponding structural or component changes are made to the position or hardware in the system of the present invention, or simple replacements are made to meet the requirements, its essence still adopts the dispersion spectral lidar of the present invention, so it should be regarded as within the protection scope of the present invention.

[0095] It can be understood that the above content is a further detailed description of the present invention in combination with specific / preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several alternatives or variations can be made to these described embodiments, and these alternative or variation methods should all be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "preferred embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention.

[0096] In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. Additionally, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the scope defined by the appended claims.

[0097] Furthermore, the scope of the present invention is not intended to be limited to the specific embodiments of the processes, machines, manufactures, compositions of matter, means, methods, and steps described in the specification. Those of ordinary skill in the art will readily understand that the present disclosure, processes, machines, manufactures, compositions of matter, means, methods, or steps that currently exist or will later be developed can be utilized to perform substantially the same functions or achieve substantially the same results as the corresponding embodiments described herein. Accordingly, the appended claims are intended to include within their scope these processes, machines, manufactures, compositions of matter, means, methods, or steps.

Claims

1. A dispersion spectrum photosensitive component, characterized in that, Comprising: A diaphragm, a collimating device, a filter, a dispersive device, and an array detector arranged in sequence along the incident optical path; Wherein, the diaphragm receives the signal light beam and the ambient light beam from the outside and is collimated into a parallel beam by the collimating device. The diaphragm limits the field of view angle, and only the beam within the field of view angle can pass through the diaphragm and be incident on the collimating device; the filter filters the parallel beam so that only the narrow-band wavelength beam centered on the central wavelength of the signal light passes through; the dispersive device disperses the incident narrow-band wavelength beam in one direction according to the wavelength, so that light of different wavelengths is incident on different positions on the surface of the array detector. Only part of the pixels of the array detector are irradiated by the signal light and the ambient light with the same wavelength as the signal light, and the ambient light with a wavelength different from the signal light will not overlap with the signal light in space. Subsequently, only the signal in the corresponding pixels of the array detector in the signal light band is read out, and the flight time of the photon is calculated based on the read signal. Further, the distance of the target is calculated according to the flight time.

2. The dispersion spectrum photosensitive component according to claim 1, wherein: The diaphragm includes at least one hole or a slit.

3. The dispersive spectral photosensitive component according to claim 1, wherein: The dispersive device includes at least one dispersive element, and the dispersive element includes one or a combination of a prism, a grating, a dispersive hologram, and a waveguide dispersive element.

4. The dispersion spectrum photosensitive component according to claim 3, wherein: The dispersive device further includes one or a combination of a lens, a lens group, a microlens array, and a mirror.

5. The dispersion spectrum photosensitive component according to claim 3, wherein: The waveguide dispersive element includes an input coupler, a beam splitter, a combiner, an output coupler, and a waveguide.

6. The dispersive spectral photosensitive component according to claim 1, wherein: The array detector includes a plurality of pixels, and the pixels are SPADs.

7. The dispersion spectrum photosensitive component according to claim 1, wherein: The collimating device includes a waveguide transmission element, and the waveguide transmission element includes an input coupler, a waveguide, and an output coupler.

8. The dispersive spectral photosensitive component according to claim 1, wherein: The filter is placed outside the diaphragm in the optical path, or between the diaphragm and the collimating device, or between the collimating device and the dispersive device, or between the dispersive device and the array detector.

9. A receiving end of a dispersion spectrum lidar, characterized in that, Comprising: A receiving optical component for receiving at least part of the signal light beam reflected back by the target and part of the ambient light beam and incident on the dispersive spectral photosensitive component according to any one of claims 1-8, and the dispersive spectral photosensitive component disperses the incident beam to distinguish different wavelengths in space.

10. A dispersion spectral lidar system, characterized in that, Comprising: A transmitting end configured to emit a signal light beam; The dispersive spectral lidar receiving end according to claim 9; A control and processor for controlling the dispersive spectral photosensitive component in the dispersive spectral lidar receiving end to screen out the incident beam signal with the same wavelength as the signal light beam, and calculating the flight time of the photon based on the incident beam signal.

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